Funnel spinning of viscose rayon filaments



March 4, 1969 AKIHIRO ISOBE ET AL 3,431,336

FUNNEL SPINNING OF VISCOSE RAYON FILAMENT5 Filed Oct. 19, 196'? United States Patent 41/ 69,903 U.S. Cl. 264--l69 Int. Cl. Dllld /06; DOM 3/10 5 Claims ABSTRACT OF THE DISCLOSURE A vicose funnel spinning process wherein a liquid capable of dissovling the vicose liquid is passed through the funnel in advance of the initiation of the regular spinning, so as to avoid possible clogging of the spinneret orifices by deposition of the viscose.

This invention relates to a process for the funnel spinning of viscose rayon filaments.

Various and considerable efforts have hitherto been directed to the acceleration of the spinning process of viscose rayon filaments, utilizing the highly developed funnel type coagulation bath. In this conventional kind of rayon spinning process, a vertically extending funnel is employed which is formed at its top end with an enlarged hollow head mounting therein a spinneret in a dipped manner. For accelerating the spinning process according to a conventional technique, it has been already proposed to feed the coagulating bath liquid at a substantially elevated pressure to the sealed head for increasing correspondingly the flow velocity of the liquid passing downwards through the funnel, thereby realizing a high speed spinning. Although an increased operating eificiency is attained according to this improved process on account of its high speed spinning nature, such a considerable ditliculty is encountered at the initial period of the spinning process that spinning orifices of the spinneret are clogged with the viscose solution coagulated and deposited in and around the orifices at the initiation of the spinning step. This kind of grave difficulty will arise also in the case of other conventional viscose spinning process using stationary coagulating bath.

It should be noted that manual removal of the clogged substance from the spinneret orifices is practically impossible, since the spinneret is mounted within the funnel head in a completely diped manner in the bath liquid.

As a counter measure to overcome the above ditficulties, it has already been proposed to increase considerably the flowing velocity of the coagulating acid bath liquid at the initial stage of the viscose spinning and reduce it to its regular speed after the extruded viscose from the spinneret orifices is coagulated in the course of passage through the funnel and in flowing contact with the fluid bath liquid and finally taken out from the lower end of the funnel in the form of shaped filaments to be Wound up by a winding apparatus. When carrying out this improved process, however, frequent breakage of the extruded and 'coagulated filaments may occur under the influence of the increased fluid velocity of the coagulation liquid at the initial stage of viscose spinning. On the other hand, it is necessary to consume a considerable length of time in order to establish the constant and regular spinning conditions when counted from the start of the spinning process newly initiated, leading to failure of the industrial utilization.

It is therefore the main object of the present invention to provide an improved Spinning process employing the funnel spinning principle, yet without any fear of the aforementioned conventional drawbacks.

Another object is to provide an improved funnel spinning process of the above kind which is capable of operating at a higher spinning velocity substantially with out fear of filament breakage.

Still another object is to provide a spinning process of the above kind which is capable of keeping the spinneret orifices always in clean or nonclogged conditions.

For the realization of the aforementioned objects, the present invention in its broadest aspect resides in a viscose spinning process relying upon the funnel spinning technique, said process being characterized by that at the starting period of the spinning process a liquid different from the bath liquid yet capable of dissolving the viscose liquid, preferably water, is led to flow through the funnel zone, and then the liquid is changed off to the regular bath liquid.

These and other objects, nature and advantages of the invention will be more fully understood when read in the following detailed description of the invention by reference to the accompanying drawing illustrative only in a schematic sectional representation of a preferred embodiment of the spinning apparatus adapted for carrying out the invention.

In the following, as a guide for better and preparatory understanding of the present inventive process, a spinning apparatus adapted for carrying out it will now be described briefly by reference to the accompanying drawmg.

In the drawing the numeral 1 denotes a spinneret which is formed therein as co nventionally with a number of extrusion orifices, although not shown. Viscose spinning liquid is supplied ot the spinneret 1 as again conventionally from a supply source, preferably a metering gear pump at 12 through a supply piping 2, the lower end of the latter projecting into the interior space of the enlarged head chamber 11 of a funnel 3 extending vertically as shown. The spinneret 1 is mounted stationary within the funnel head 11 in a dipped manner.

Liquid supply pipe 4 is kept in fluid communication with both pipes 5 and 7, the former pipe 5 being connected through a valve means 6 with a proper supply source which may preferably be a pump 13 adapted for the delivery of a certain kind of liquid, for instance, water which is capable of dissolving viscose. The latter pipe 7 is also connected through a valve means 8 with a second supply cource which may preferably be a pump 14 adapted for the supply of coagulation bath liquid having a conventionally employed acid composition. Below the lower end of the funnel 3, there is provided a receptacle or tank 9 adapted for collecting the discharged liquid and discharging it to a convenient place through a dischaged piping, although not shown. Outside of and remote from the tank 9, a guide 10 preferably in the form of a freerotatable or positively driven roller as shown, is also provided so as to guide the coagulated viscose filaments emerging from the lower end of the fluid bath tube 3, in a deflecting manner therefrom.

Before initiation of the regular spinning process, an operator closes the valve 8 in the second pipe 7 and opens the valve 6 in the first pipe 5, thereby feeding through pipes 5 and 6 into the interior space of the funnel head 11 provisionarily a certain kind of liquid, preferably water, alkaline aqua solution or the like, which is thus different from the regular bath liquid, yet capable of dissolving viscose in and on the spinneret 1, thence the fed liquid is led to pass through the tube 3. Upon ascertaining the appearance of the cleanin liquid at the lower end of the funnel 3, the operator actuates the spinning pump 12 so as to feed viscose liquid through the pipe 2 to the spinneret 1, for initiating the viscose extrusion Step from the extrusion orifices thereof. Under these conditions, it will be clear that the extruded viscose is not caused to coagulate, but dissolved into the cleaning liquid during passage through the funnel 3. The operator opens gradually the valve 8 in the pipe 7, while he is closing gradually the hitherto opened valved 6 in the pipe 5, thereby gradually changing off the cleaning liquid flow to the regular fluid bath liquid to pass through the funnel 3. At the end of this change-off operation, the extruded viscose will be subject to the coagulating action provided by the now flowing-down bath liquid through funnel 3, so as to form regular coagulated filaments in the form of a bundle, as at A shown in the drawing, which emerges from the lower end of the funnel and is led to the deflection guide at 10. Then, the bundle, after passing through a drafting zone, not shown, will be wound up by a certain winding mechanism, again not shown.

From the foregoing, it will be clear that with the use of the aforementioned spinning assembly, a different flow liquid which is capable of dissovling the viscose, is constantly brought into contact with the spinneret at the initial operating period of spinning process. Under these conditions, otherwise floating viscose masses coagulated in the tube can not be found to exist, and the extrusion orifices are kept always in their highly cleaned, nonclogged condition, even in the initial operating period, while on the contrary to the conventional technique the initially fed and extruded viscose is contacted, even from the beginnning of the spinning process, with the coagulation bath liquid with considerable fear of initial coagulation of the viscose which will lead to disadvantageous clogging of the orifices, as well as considerable fouling of the exposed effective surface of the spinneret, leading in turn to a smooth, effective and non-interrupted formation of viscose filaments.

The inventive process will now be described more in detail hereinbelow by reference to several preferred numerical examples:

EXAMPLE 1 While using a spinning assembly shown and described in the foregoing, the valve 8 in the pipe 7 is closed at first and then the valve 6 in the pipe is opened, in advance of feeding a viscose solution, having a conventional composition, to the spinneret 1 formed with 26 extrusion orifices, each having a bore of 0.07 mm. Then the pump 13 is operated to feed water through the pipes 5 and 4 to the funnel head 11 and the viscose pump 12 is operated to feed the viscose through the feed pipe 2 to the spinneret 1. After lapse of 1 minute, the water valve 6 is gradually closed, while the second or bath control valve 8 is gradually opened upon energization of the pump 14. In this way, the liquid flowing through the funnel 3 has been changed off from water to a regular coagulation bath liquid, having a composition: H 50 160 g./liter; Na SO 300 g./liter and ZnSO 15 g./liter. The extrusion orifices could be kept, even in the initial period of spinning, in a completely clean condition for the desirous extrusion of the viscose, without any fear of breakage of the coagulatcd filaments which were, upon emerging from the lower end of the funnel 3, stretched and wound up in the regular way. Upon passage through the deflecting filament guide at 10. The regular spinning was carried into effect at an extrusion velocity of 150 meters per minute and the filaments were of denier.

EXAMPLE 2 In the process set forth in Example 1, the water was replaced by an alkaline aqua solution, containing an alkali, preferably NaOH, KOH or the like, in the ratio of 1:8 g./liter. Other operating conditions were same as before. In this example, no fear of clogging the extrusion orifices was experienced, and there was also no filament breakage. The spinning speed amounted to meters per minute and the produced filaments were of denier.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present examples are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What we claim is:

1. A viscose spinning process operating upon the funnel spinning technique, said process comprising: feeding a liquid different from the regular bath liquid, yet capable of dissolving the viscose, preferably water through the funnel zone at the initiation stage of the spinning process, extruding the viscose solution through orifices and leading to pass through said funnel zone, and then feeding the regular coagulation bath liquid through said zone after stopping the feed of said first liquid.

2. A viscose spinning process as set forth in claim 1, wherein said first liquid is an alkaline solution.

3. A viscose spinning process as set forth in claim 1, wherein said first liquid is fed for one minute or so.

4. A viscose spinning process as set forth in claim 2, wherein said alkaline solution containing about 1.8 g. of NaOH per liter of liquid.

5. A viscose spinning process as set forth in claim 1, wherein the spinning speed is selected to be about 130- 150 m./min.

References Cited UNITED STATES PATENTS 3,049,755 8/1962 Aizana et al 264-l81 3,056,163 10/1962 Deis 264169 X JULIUS FROME, Primary Examiner.

I. H. WOO, Assistant Examiner.

US. Cl. X.R. 

